Hydrostatic bumper jar



Jun 3, 1958 Filed Feb. 16. 1955 ArroR/y/fy United States Patent C f HYDROSTATIC BUMPER JAR Albert L. Burns, Jr., and Jack Chadderdon, Houston, Tex., assignors to Houston Oil Field Material Company, Inc., Houston, Tex., a corporation of Delaware Application February 16, 1953, Serial No. 337,092

Claims. (Cl. 255-27) or to cut off and recover pipe or junk therein, it is desirable to utilize a jar in connection therewith to aid in successfully removing and/or recovering the pipe or junk.

sirable to provide a downward jar such as, for example, to aid in freeing the fish, which may be pipe, tools, various elements and the like stuck in the well bore. Conventional bumper jars utilized in the industry must be provided with additional weight, such as heavy pipe or drill collars, in order that enough weight is provided to produce a downward jar of the desired force. The use of drill collars and the like to provide such weight is expensive, requires additional time and, many times, such additional weight providing means are not available at the well which further delays operations. In addition, many times drill collars, which are ordinarily attached or secured above the bit to give it weight, are stuck in the well bore and it is not desirable to place more drill collars in the well bore. Also, when using a bumper type jar with tubing, drill collars ordinarily are not available at the well.

It is therefore a general object of the present invention to provide a bumper jar in which it is not necessary to provide auxiliary weight to provide a jarring action of the desired force.

It is a more particular and major object of the present invention to provide a bumper jar which is actuated by the hydrostatic pressure in the well bore to provide the desired jarring action.

A still further object of the present invention is the provision of a jar of the bumper type, that is, a jar which jars downwardly, which automatically provides a jarring action of a magnitude substantially equal to the hydrostatic pressure in the bore at the place the jarring takes place.

A still further object of the present invention is the provision of a jar of the bumper type which is simple, inexpensive to manufacture and repair, easily and readily maintained and repaired, and which is efcient and rugged in use.

Other an-d further objects and features will be apparent from the following description of an example of the invention, given for the purpose of disclosure, and taken in connection with the accompanying drawing, where like character references designate like parts throughout the several views, and where Many times in shing and other operations, it is dethe upwardly extending shoulder 34 on the uce Fig. 1 is a side elevation, in section, illustrating a bumper jar constructed according to the invention and shown in extended position,

Fig. 2 is a view similar'to Fig. 1, but illustrates the jar in jarring position, and

Fig. 3 is a cross-sectional view taken along the line 3-3 of Fig. 2.

Referring now to the drawing, the bumper jar comprises the body 10 which may be of any desired shape and, preferably, is an elongated tubular member and includes an internal shoulder or reduced diameter portion formed at one end, and a closed second end thereby forming a closed chamber interior of the body 10 into which the reduced mandrel or stem portion 12 of the support 11 slidably extends.

The reduced diameter portion at the upper end of the body 10 is here accomplished by threading thereto the sub 14 of reduced internal diam`eter through which the stem 12 slidably extends, and as best seen in Fig. 3, the inner periphery of the sub 14 and the outer surface of the stern 12 are multisided or hexagonal. Thus coacting guide and slide surfaces are provided in thespb 14 and on the stem 12 in order that rotation may be imparted from above the bumper jar to the pipe or tools secured therebelow.

Threaded at and forming a closure for the lower end of the body 10 is the sub or coupling 16 which has the downwardly extendingthreaded pin 18 to which pipe means may be secured for connecting the body .to tools or pipe and the like. Since such pipe, tools and the like form no part of the present invention, only a fragmentary section 2t) is illustrated to indicate any of the conventional tools, elements, pipe and the like which may be secured to and below the jar.

The upper end of the support 11 has an enlarged head 22 which has the upstanding threaded box 24 by which the device may be threadedly secured to the operating string of pipe indicated by the numeral 26. While not shown the operating string of pipe, by which the device is lowered into a well bore, extends to the surface (not shown).

The lower end of the mandrel or stem 12 has the enlarged portion or piston 28 which is slidable in the body 10 and has suitable piston rings, such as the O- rngs 30, to provide a snug and Vsealing fit of the piston 28 in the body 10, the latter being in effect a piston cylinder. The piston 28 has an outer diameter greater than the inner diameter of the sub 14 and is confined in the interior of the body 10 by means of the downwardly projecting shoulder 32 on the upper connection or sub 14 and upper end of the lower coupling or tool joint 16.

As illustrated, the various elements -may be hollow or have a passage for circulation of drill fluid therethrough. In such event there may be a hollow wash pipe or tube 36 which may be threadedly or otherwise secured to the lower end of the piston 28 and slidably secured in the lower coupling or sub 16 although it may otherwise be secured. The wash pipe or tubing 36 may be secured in any satisfactory manner and should be sealed with respect to the lower coupling 16 and the support 11.

' As illustrated, a satisfactory arrangement is to provide a stuffing box in the lower coupling 16. This may be accomplished by providing a counter-bored portion 38 into which the packing 40 is disposed and compressed against the outer surface of the tube 36 by the gland 42 threaded in the counter-boredy portion 38. If desired, seal or packing means may be provided at the upper end of the wash pipe or tube 36; although, the arrangement il- I lustrated is satisfactory.

A plurality of ports 44'are provided in the upper por- I Patented June 3, 1958 tion of the body to permit entry of hydrostatic pressure inthe wellbore (not shown) to exert a downward force on the upstanding shoulder 46 of the piston 28 thereby causing the piston 28 to move violently downwardly when tensionl on the support 11 from the string of pipe 26 Visreleased and thevjar is in the position illustrated in Figure 1, as will be apparent later.

In operation, the bumper jar may be threaded in a manipulating string of pipe 26 extending from the surface, and the bottom of the jar may be threaded to a pipe section having a suitable grappling or fishing tool thereon or may be secured directly to the grappling or fishing tool in the event a fishing job is being performed.

The bumper jar is utilized in a well bore in which there is drilling iuid or other fluid under hydrostatic pressure and the spacebelow the lower end of the piston 28 and the upper end 34 of the sub 15 is under a vacuum or negative pressure head due to the fact that it is sealed ot from the hydrostatic pressure in the well bore. Thus, when it is desired to jardownwardly, for example, when the bumper jar is attached tostuek pipe or tools or other objects, the manipulating string of pipe 26 may be elevated thereby raising or extending the support 11 and the piston 28 into the position illustrated in Fig. l. Upon release of the manipulating pipe 26 from tension or lifting forces, the hydrostatic pressure of the well fluid in the well bore enters through the ports 44 thereby driving the piston 28 violently downward relative to the body 10, the latter remaining substantially stationary due to its being secured to the stuck object, thereby causing the lower annular shoulderdt, which may be a hammer surface, on the lower portion of the head 22 of the stem or mandrel 12 to strike the upper annular shoulder 50, which may be considered an anvil surface, of the sub 14 forming the upper end of the body 10, a violent blow thereby jarring the body 10 downwardly and the section of pipe or tools 2t) secured therebelow. While the weight of manipulating string of pipe 26 aids or may aid in the downward movement of piston 28, the weight of this manipulating string of pipe 26 is somewhat overcome by the buoyancy eifect of the drilling fluids in the Well bore and friction between the manipulating string of pipe 26 and the well bore which often prevent an abrupt downward movement of it. The use of the hydrostatic pressure, however, in the well bore causes to a great extent this downward'movement and causes a violent jarring action. It is appreciated that in deep wells the hydrostatic pressure exerted by the columns of drilling or other Huid therein is of considerable magnitude. The downward jar or blow is effective in aiding to jar loose sections of pipe or tools which may be lodged or stuck in the well bore, and continued jarring may be effected by merely raising or applying tension to the manipulating string of pipe 26 extending to the surface, thereby producing a vacuum or negative head of pressure, as indicated, the hydrostatic pressure in the well bore providing the jarring action upon relaxing the lifting'force or tension of the manipulating pipe.

Well bores ordinarily are quite deep and it is apparent that a column of fluid or drilling mud in a well bore will provide a considerable hydrostatic pressure thereby producing a vigorous and sharp jar downwardly which avoids the necessity of providing additional weight, such as heavy drill collars and the like, with all the attendant problems and expense, to provide the required jarring action.

While the lower annular shoulder 48 of the head 22. and the upper annular shoulder St) of the sub 14 have been indicated as the hammer and anvil surfaces, rcspectively, it is apparent that the lower annular shoulder 52 at the bottom of the piston 28 and the upper annular shoulder 34 at the upper end of the lower sub or coupling 16 may constitute the hammer and anvil surface, respectively, to provide the jarring action. It is only 4 l necessary to lengthen or shorten the stem or mandrel 12 to provide a jar at either place. Additionally, the surfaces may be provided to be impacted substantially simultaneously. For practical operations, however, it is presently preferred to provide the hammer and anvil surfaces 43 and 50 at the lowerend of the upper head 22 and the upper end of the sub 14 in order that the closely-confined piston 28 is not damaged in its movement in the body or piston cylinder 10.

As indicated previously, rotation may be imparted through the bumper jar by means of the hexagonal or multisided outer surface of the stem 12 and the inner surface of the sub 14 so that the pipe section 2t) or tools therebelow, such as a milling, outside or inside cutting, drilling, reaming and like tools, and spears, taps and the like may be rotated in the usual manner.

While the bumper jar is indicated as threaded to the manipulating pipe 26, it is apparent that it may be secured to. a wire line,.fif desired, inasmuch as the downward movement of the pistonZSis caused by the hydrostatic pressure inthe ywell bore.

The mandrel 12 may tit loosely in the upper connection 14 and, in this event, hydrostatic pressure enters between the mandrel Hand the connection 14 and the ports 44- may be omitted. .If desired, a combination of a loose tit and the ports 44 may be provided.

ln the event it is not necessary or desirable to circulate iiuid through the jar, thesupport and piston and other elements may be provided without a passage and the tube 36 omitted. Also, any typevof suitable means may be used to seal the piston cylinder under the piston from The bumper jar ofthe present invention is therefore well suited to attain the objects set forth above and others inherent therein. Various rearrangements of parts and changes in details may be made, and, accordingly, it is desired to be limited only iby the spirit of the invention as dened by the scope of the appended claims.

What is claimed is:

1. A hydrostatic jar for use in a well bore having hydrostatic pressure therein comprising, in combination, an elongate hollow body, said body including an internal shoulder formed at one end of the body and -a closed end at the other end of the body, a hollow support adapted to be secured to operating means in the well bore, Vsaid support including a stem of reduced diameter extending into the body through the shoulder, a piston on the lower endof said stem snugly slidable in said body, a hammer surface on the piston, an anvil surface carried by the body and engageable by the hammer surface on movement of the stem relative to the body, a tube extending through the other end of said body and secured to the piston, said tube being in fluid communication with the hollow portion of the stem and the support, seal meansy sealing the tube from the interior of .the body, coupling means on the body for connecting the body to tools or pipe, and means in the body permitting entry of the hydrostatic pressure into the interior of the body between the piston and the internal shoulder whereby said hydrostatic pressure urges said piston to bring the hammer and anvil surfaces into violent impact.

2. A hydrostatic jar for use in a well bore having fluid under hydrostatic pressure therein comprising, in com bination, an elongate hollow body having a piston cylinder, an internal shoulder formed at one end of the piston cylinder, the other end of said cylinder being closed, a hollow support adapted to be secured to an operating string of pipe in Athe well bore, said hollow support including a stem of reduced diameter extending into the end of said piston cylinder through the shoulder, said body and stem having coacting guide and slide surfaces preventing rotation of the stem relative to the body, a piston on said stem snugly slidable in said body, a hammer surface on the piston, an anvil surface carried by the body and engageable thereby on movement of the stem relative to the body, a tube secured to the piston in fluid communication with the hollow portion of the stem and slidably disposed in an extending through the other end of the body, seal means sealing the tube from the interior of the piston cylinder, coupling means on the body for connecting the body to tools or pipe, and means in the body permitting entry of fluid under said hydrostatic pressure in the well bore into the interior of the body between the piston and the internal shoulder whereby said hydrostatic pressure urges said piston to bring the hammer and anvil surfaces into violent impact.

3. A hydrostatic jar for use in a well bore having hydrostatic pressure therein comprising, in combination, an elongate tubular body having a piston cylinder, said body being open at its upper end, an internal reduced diameter portion at the upper end of the body, a hollow support adapted to be secured to a string of manipulating pipe, a hollow mandrel of reduced diameter depending from said support and extending downwardly through said reduced diameter portion into the piston cylinder, a hollow piston on said mandrel slidable in said piston cylinder, means to prevent relative rotation of said mandrel and said body, a coupling member having a passage therethrough connected to and closing the lower portion of the piston cylinder, a hammer surface carried by the mandrel, an anvil surface on the body below the hammer surface and engageable thereby on downward movement of the mandrel, a tube slidable in the passage of the coupling member extending into the piston cylinder and connected to the hollow piston, means sealing the tube and passage, and means in the body permitting entry of hydrostatic pressure between the piston and the reduced diameter portion of the body whereby said hydrostatic pressure urges said piston to bring the hammer and anvil surfaces into violent impact.

4. The hydrostatic jar of claim 3 where the hammer y surface is a downwardly facing annular shoulder formed at the lower end of the support, and the anvil surface comprises the upper endof the body.

5. The hydrostatic jar of claim 3 where the hammer surface is provided on the lower surface of the piston, and the anvil surface is provided at the lower end of the piston cylinder.

6. The hydrostatic jar of claim 3 where the means to permit entry of the hydrostatic pressure into the upper end of the body comprises ports disposed in the upper end of the piston cylinder.

7. A hydrostatic jar for use in a well bore having hydrostatic pressure therein comprising, in combination, an elongate hollow body, an internal shoulder formed at one end of the body, the other end of said body being closed, a mandrel adapted to be secured to an operating string in the well bore, said mandrel including a stem of reduced diameter extending into the body through the shoulder, a piston on the inner end of the stem snugly slidable in said body, a hammer surface carried by the stem, an anvil surface carried by the body engageable by the hammer surface on relative movement of the body and stem, a coupling element on the body for securing the body to a member to be jarred, and means in the body establishing fluid communication between the hydrostatic pressure and the interior of the body on one side only of the piston whereby said hydrostatic pressure urges said piston to bring the hammer and anvil surfaces into violent impact.

8. A hydrostatic jar for use in a well bore having hydrostatic pressure therein comprising, in combination, an elongate hollow body, said body including an internal reduced diameter portion at one end of the body and a closed end at the other end of the body thereby forming a piston chamber in the body, a stem adapted to be secured to an operating string in the well bore, a portion of said stem extending into said body through said reduced'diameter portion, said stem including a pistonv snugly slidable within said piston chamber, a hammer surface carried by the stem, an anvil surface on the body engageabie by the hammer surface on movement of the stem relative to the body, means on the closed end of the body for connecting said closed end of the body to a member to be jarred, and means in the body permitting the hydrostatic pressure in the well bore to enter the piston chamber and bear against one side of the piston whereby said hydrostatic pressure urges said piston to bring the hammer and anvil surfaces into violent impact.

9. A hydrostatic jar for use in a well bore having hydrostatic pressure therein comprising, in combination, a hollow body, said body including an internal shoulder formed at one end of the body and a closed end at the other end of the body forming a piston chamber in the body, a stem adapted to be secured to an operating means in the well bore, a portion of said stem extending into said hollow body through said shoulder, said stem including a piston snugly slidable in said piston chamber, a hammer surface carried by the stem adjacent its outer end, an anvil surface carried by the body and engageable by said hammer surface on movement of said stem relative to the body, means on the other end of the body for connecting the body to a member to be jarred, and means in the body permitting the hydrostatic pressure in the well bore to enter the piston chamber and bear between the piston and the internal shoulder whereby said hydrostatic pressure urges said piston to bring the hammer and anvil surfaces into Violent impact.

l0. A hydrostatic jar for use in a well bore having hydrostatic pressure therein comprising, in combination, an elongate hollow body, said body including an internal shoulder formed at one end of the body and a closed end at the other end of the body thereby forming a piston chamber in the body, a stem adapted to be secured to operating means in the well bore, a portion of said stem extending into said body and through said shoulder, said stem including a piston snugly slidable in the piston chamber, a hammer surface carried by the stem adjacent its outer end, an anvil surface carried by the body, said anvil surface engageable by the hammer surface on movement of the stern into the body, said stem, piston and piston chamber having a fluid passageway extending therethrough, seal means sealing the passageway from the interior of the piston chamber, means on the other end of the body for connecting the body to a member to be jarred, and means in the body permitting entry of the hydrostatic pressure of the well bore into the body between the piston and the internal shoulder whereby said hydrostatic pressure urges said piston to bring the hammer and anvil surfaces into violent impact.

References Cited in the le of this patent UNITED STATES PATENTS 1,695,033 Smith Dec. 11, 1928 2,180,223 Collett Nov. 14, 1949 2,733,045 Burns Jan. 31, 1956 

